Sardinia-Piedmont

Sardinia-Piedmont (1458-1861), also called Sardinia or Piedmont, was a union of the kingdoms of Sardinia and Savoy founded in 1720 after years of split rule between the Aragonese Empire of Spain (controlling Sardinia) and the House of Savoy of Italy (controlling Savoy/Piedmont). In 1861 they unified Italy under their banner with French aid.

History
Sardinia was ruled by the Aragonese Empire from 1323 to 1410 and by the Spanish Empire from then until 1720, when the country was ceded to the Kingdom of Savoy. Sardinia was united with Savoy that year, and not only did they include the island of Sardinia, but also Piedmont in northern Italy.

Sardinia was a close ally of the Austrian Empire, who were their masters. In 1796 the French Republic took over Cuneo and Turin during the Italian Campaign of the French Revolutionary Wars and forced Sardinia to have a change of allies. As a vassal of France they lost control of Piedmont in the Treaty of Campo Formio in 1797, and they were confined to Sardinia. They allied with the Coalitions against Napoleon in the Napoleonic Wars of 1805-1815, and they regained their lands in mainland Italy.

Sardinia-Piedmont gained its chance at territorial expansion in 1848 with the revolutions of Europe, and they allied with revolutionaries against the Austrian Empire in order to unify Italy; it consisted of 15 states as of 1815. They were defeated in the First Italian War of Independence of 1848-49, but in the war of 1859-61, they took all of northern Italy with French aid. Giuseppe Garibaldi and the Redshirts landed in southern Italy in 1860 and conquered the Kingdom of the Two Sicilies and agreed to give the lands to Sardinia, thus unifying Italy (apart from Venice and the Papal States). In 1866, with Prussian aid, Sardinia-Piedmont gained control of Venice, and in 1870 they occupied Rome and Pope Pius IX was held as a prisoner in the Castel Sant'Angelo. But by 1861 they had already declared themselves to be the Kingdom of Italy.